Question

Regular triangular pyramid has 6 cm long base edge and slant height k=9 cm. Find the lateral area of the pyramid.

Answer 1

81 cm²

Explanation:

Since, the lateral face of a triangular pyramid is a triangle,

Given,

The base edge or the base of one lateral face of pyramid, a = 6 cm,

And, the slant height or the height of the face, k = 9 cm,

Thus, the area of one lateral face of the pyramid,

`A=(1)/(2)* a* k`

`=(1)/(2)* 6* 9`

`=(54)/(2)`

`=27\text{ square cm}`

We know that, a Regular triangular pyramid has 3 lateral faces,

Hence, the total lateral area of the pyramid,

`L.A.=3*\text{ The area of one lateral face}`

`=3* 27`

`=81\text{ square cm}`